<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>控制样式</title>


    <style>
        .d1{
            border: 1px solid red;
            width: 100px;
            height: 100px;
        }

        .d2{
            border: 1px solid blue;
            width: 200px;
            height: 200px;
        }


    </style>
</head>
<body>
    <div id="div1">
        div1
    </div>

    <div id="div2">
        div2
    </div>

    <script>
        var div1 = document.getElementById("div1");
        div1.onclick = function(){
            //修改样式方式1
            div1.style.border = "1px solid red";
            div1.style.width = "200px";
            //font-size--> fontSize
            div1.style.fontSize = "20px";

        }


        var div2 = document.getElementById("div2");
        div2.onclick = function(){
            div2.className = "d2";
        }


    </script>
</body>
</html>